1. Field of the Invention
The present invention relates to a solenoid coil for an NMR signal and a probe for an NMR.
2. Description of Related Art
In the solenoid coil, a homogeneity of a static magnetic field is lowered in an outer side from a coil end. There has been known a structure for circulating an electric current in an inverse direction to a main solenoid or generating a magnetic field in an inverse direction to the main solenoid coil by arranging a cancel coil in an outer side in an axial direction of the main solenoid coil, in order to increase the homogeneity of the static magnetic field of the solenoid coil (for example, refer to patent document 1 (JP-A-7-23923 (abstract)).
The patent document 1 narrows a sensitive area so as to prevent a signal from being mixed from a space having a low homogeneity of the static magnetic field, by arranging the cancel coil, thereby circulating the electric current in the inverse direction to the main solenoid coil or generating the magnetic field in the inverse direction to the main solenoid coil. However, in accordance with this method, the sensitive area of the solenoid coil becomes narrow.